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Analog Devices Inc./Maxim Integrated MAX861ISA+
- Part No.:
- MAX861ISA+
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
MAX861ISA+.pdf
- Description:
- IC REG CHARG PUMP INV 50MA 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:241
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Product details
Overview
MAX861ISA+ from Maxim Integrated is a frequency-selectable, 50mA switched-capacitor voltage inverter/doubler IC that converts +1.5V to +5.5V inputs to inverted outputs or +2.5V to +5.5V inputs to doubled positive outputs. It features three user-selectable switching frequencies (13/100/250 kHz), 12Ω output resistance, 87% efficiency at 50mA, and 1µA shutdown current. It serves as a compact, inductorless power solution for portable medical instruments and handheld test equipment.
For engineers reviewing the MAX861ISA+ datasheet, MAX861ISA+ pinout, MAX861ISA+ application, or MAX861ISA+ equivalent, key selection criteria include its SO-8 package compatibility, LV pin configuration for mode selection, FC pin-driven frequency trade-offs between capacitor size and quiescent current, and its role as a drop-in upgrade path from ICL7660/MAX660 in space-constrained battery-powered systems.
Technical Context
The MAX861ISA+ implements a BiCMOS charge-pump architecture with direct oscillator-to-switch coupling-no frequency division-enabling precise control of switching frequency via the FC pin (GND/OUT/VDD). Its LV pin determines operating mode: grounded for inverting, connected to OUT for doubling, enabling dual-function flexibility without external component changes.
It delivers regulated-equivalent performance through low-output-resistance design (12Ω typical) and stable voltage conversion across load currents up to 50mA, with output droop of only 600mV at full load. Shutdown functionality reduces supply current to <1µA, while startup requires input supply capability of ≥90mA transient headroom above load demand.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Output Current | 50mA max continuous - supports moderate-power analog rails without inductors |
| Switching Frequencies | 13/100/250 kHz - enables optimization of capacitor size (2.2–68µF) vs. EMI vs. quiescent current |
| Output Resistance | 12Ω typical - defines output voltage droop: e.g., -5.0V → -4.4V at 50mA load |
| Efficiency | 87% at 50mA - high conversion efficiency preserves battery life in portable systems |
| Shutdown Current | <1µA - enables ultra-low-power sleep modes in always-on instrumentation |
| Input Voltage Range | +1.5V to +5.5V (inverter); +2.5V to +5.5V (doubler) - covers single-cell Li-ion to 5V rail operation |
| Operating Temp | -25°C to +85°C - qualified for industrial and portable medical environments |
Pinout & Package
MAX861ISA+ is housed in an 8-pin SO (Small Outline) package, 3.9mm × 4.9mm, RoHS-compliant, with standard 1.27mm pitch and gull-wing leads.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 FC | Frequency Control Input | Selects switching frequency: GND = 100kHz, OUT = 250kHz, VDD/open = 13kHz |
| 2 C1+ | Flying Capacitor Positive Terminal | Connects to positive plate of flying capacitor C1; critical for charge transfer timing |
| 3 GND | Ground Reference | Primary return path for internal switches and external capacitors; must be low-impedance |
| 4 C1− | Flying Capacitor Negative Terminal | Connects to negative plate of flying capacitor C1; forms charge-transfer loop with C1+ |
| 5 OUT | Output Terminal | Delivers inverted (−VIN) or doubled (+2VIN) output; drives load to GND or VDD respectively |
| 6 LV | Mode Selection Input | GND = inverter mode; OUT = doubler mode; floating allowed only for VIN >3V in inverter config |
| 7 SHDN | Active-Low Shutdown | Pulled low disables all switching; pulled high (VDD) enables operation; must not float |
| 8 VDD | Positive Supply Input | Accepts +1.5V to +5.5V; powers internal logic and charge-pump switches |
Key Features
| Feature | Design Value |
|---|---|
| Invert or double input voltage | Single IC supports both topologies via LV pin configuration-no BOM change required |
| Three selectable switching frequencies | Enables EMI mitigation (e.g., avoid 100kHz-sensitive ADC clocks) while optimizing capacitor cost/size |
| 12Ω output resistance | Ensures predictable load regulation: ≤600mV droop at 50mA, simplifying analog rail design |
| 1µA shutdown supply current | Extends battery runtime in intermittent-use devices like handheld meters and point-of-care sensors |
| SO-8 package compatibility | Direct PCB replacement for legacy ICL7660/MAX660 sockets with only SHDN pin rewiring |
Applications
| Portable Medical Instruments | Hand-Held Test Equipment |
|---|---|
Use Scenario: Powering bipolar op-amp rails in battery-operated ECG front-ends or glucose meter analog signal chains. IC Role / Device Role / Timing Role: Voltage inverter generating clean −3.3V or −5V from a single +3.3V or +5V Li-ion-derived supply. Use Value: Eliminates magnetic components and reduces board area by >40% versus inductive solutions, meeting IEC 60601 leakage and EMI requirements. | Use Scenario: Providing dual-rail ±5V supplies for portable oscilloscope front-end amplifiers and ADC drivers. IC Role / Device Role / Timing Role: Configured as inverter (LV = GND) to generate −5V, paired with main +5V rail for symmetrical analog biasing. Use Value: Achieves 87% efficiency at 50mA load while maintaining <10mVpp ripple with 4.7µF/2.2µF ceramic caps-critical for 12-bit measurement accuracy. |
| Interface Power Supplies | Operational-Amplifier Power Supplies |
Use Scenario: Generating isolated RS-232 or RS-485 transceiver bias voltages in compact IoT gateways. IC Role / Device Role / Timing Role: Doubler (LV = OUT) producing +10V from +5V microcontroller rail to drive transceiver charge pumps. Use Value: Delivers stable +10V at 20mA with <1% line/load regulation-enabling robust long-cable communication without external LDO post-regulation. | Use Scenario: Biasing precision op-amps in portable data loggers requiring low-noise ±2.5V rails. IC Role / Device Role / Timing Role: Inverter configured with FC = GND (100kHz) to minimize capacitor ESR impact and reduce output ripple. Use Value: 12Ω output resistance and 200µA quiescent current enable rail stability under dynamic loads while maximizing battery life over multi-day deployments. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar switched-capacitor voltage converter applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| MAX860ISA+ | Lower base frequency (6/50/130 kHz); higher no-load current (2.6µA vs. 0.5µA) | Better suited for EMI-sensitive audio circuits where lower fundamental switching noise is preferred | Select when 6kHz minimum frequency avoids interference with sub-10kHz sensor signals |
| MAX660CPA+ | Higher output current (100mA); fixed 5/40kHz switching; 6.5Ω output resistance | Supports heavier loads but requires larger 10µF electrolytic capacitors and lacks frequency selectability | Choose for cost-sensitive, high-current applications where layout space allows larger caps and EMI is less critical |
Compared with MAX860ISA+ and MAX660CPA+, the MAX861ISA+ offers the highest switching frequencies (up to 250kHz), enabling smallest external capacitors (as low as 2.2µF), while maintaining identical 50mA rating and SO-8 footprint-ideal for next-generation miniaturized instrumentation where board area and high-frequency noise immunity are prioritized.
Availability
MAX861ISA+ is available at Aetrix Electronics and suitable for portable medical instruments, hand-held test equipment, interface power supplies, and operational-amplifier power supplies requiring stable component supply, long-term lifecycle support, and RoHS-compliant sourcing.
Supply support for MAX861ISA+ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Maxim Integrated (now part of Analog Devices) designs precision analog, mixed-signal, and power-management ICs for industrial, medical, and communications applications.
The MAX860/MAX861 product line was engineered to replace inductive DC-DC converters and legacy charge pumps (e.g., ICL7660) in space-constrained, battery-powered systems requiring efficient, low-EMI, inductorless voltage inversion or doubling.
FAQ
What is the maximum continuous output current specification for MAX861ISA+?
The MAX861ISA+ is rated for 50mA continuous output current under specified thermal conditions (TA ≤ +85°C, SO package). Absolute maximum rating is 60mA, but sustained operation above 50mA may exceed thermal limits or degrade output regulation. The 50mA value reflects guaranteed performance across the full −25°C to +85°C temperature range with 12Ω typical output resistance and ≤600mV voltage drop.
How does the FC pin configure switching frequency on MAX861ISA+?
The FC pin on MAX861ISA+ selects one of three discrete switching frequencies: FC = GND sets 100kHz, FC = OUT sets 250kHz, and FC = VDD (or open) sets 13kHz. These values are device-specific to MAX861 (vs. MAX860's 6/50/130kHz). Each setting directly controls the internal oscillator frequency-no division-so noise spectrum and capacitor sizing scale linearly with the selected fS.
Can MAX861ISA+ operate as both a voltage inverter and a voltage doubler on the same PCB?
Yes, MAX861ISA+ supports both topologies on the same PCB via the LV pin: connect LV to GND for inverting (e.g., +5V → −5V), or connect LV to OUT for doubling (e.g., +5V → +10V). No component changes are needed-only LV routing differs. However, both modes cannot operate simultaneously; the device must be hardwired for one function per installation.
What is the recommended capacitor configuration for MAX861ISA+ in high-frequency mode (250kHz)?
For MAX861ISA+ operating at 250kHz (FC = OUT), Maxim recommends 2.2µF for both C1 (flying) and C2 (output) capacitors using low-ESR ceramic types. This configuration minimizes board area while maintaining ≤50mA output capability and <10mVpp ripple. Larger values (e.g., 4.7µF) further reduce ripple but offer diminishing returns due to internal switch resistance dominating total ROUT.
Is MAX861ISA+ pin-compatible with the ICL7660 or MAX660?
MAX861ISA+ is not pin-compatible with ICL7660 or MAX660 due to functional pin reassignment: pin 7 is SHDN (active-low) instead of OSC (oscillator output), and pin 1 is FC instead of OSC. However, it is socket-compatible with minor rewiring-SHDN must be tied to VDD (not floated), and FC can accept existing OSC traces (GND/VDD/float all valid). Full drop-in replacement requires board-level modification.
MAX861ISA+ Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Function:
- Ratiometric
- Output Configuration:
- Positive or Negative
- Topology:
- Charge Pump
- Output Type:
- Fixed
- Number of Outputs:
- 1
- Voltage - Input (Min):
- 1.5V, 2.5V
- Voltage - Input (Max):
- 5.5V
- Voltage - Output (Min/Fixed):
- -Vin, 2Vin
- Voltage - Output (Max):
- -
- Current - Output:
- 50mA
- Frequency - Switching:
- 13kHz, 100kHz, 250kHz
- Synchronous Rectifier:
- No
- Operating Temperature:
- -25°C ~ 85°C (TA)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
MAX861ISA+ FAQ
1.How can I place an order for MAX861ISA+ through Aetrix?
Please submit a Request for Quotation (RFQ) for MAX861ISA+ on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for MAX861ISA+ reliable?
The price and inventory of MAX861ISA+ are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for MAX861ISA+ is usually 5 days.
3.What payment methods are accepted for MAX861ISA+?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for MAX861ISA+ transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for MAX861ISA+?
MAX861ISA+ orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your MAX861ISA+ order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for MAX861ISA+?
For technical support, including MAX861ISA+ datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your MAX861ISA+ requirements.
6.How does Aetrix verify that MAX861ISA+ is sourced from the original manufacturer or authorized distributors?
All MAX861ISA+ products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that MAX861ISA+ meets industry standards.
7.What is the process for return or replacement of MAX861ISA+?
All MAX861ISA+ units undergo pre-shipment inspection (PSI). If there is an issue with MAX861ISA+, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The MAX861ISA+ part is unused and in its original packaging.
Return procedure for MAX861ISA+:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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